Lopez, 27, declined a $16.7 million player option for 2015-16 ahead of the Monday deadline, as first reported by the New York Daily News.
The Nets, though, are confident that Lopez will re-sign with the team, according to sources. Sources say one possible option for both sides is for Lopez to sign a three-year max deal that would allow the center to cash in on another big deal in the future when the salary cap rises significantly due to the new television deal with ESPN and TNT.
A shorter deal for the Nets would also reduce the risk of a long-term deal with the center, who has undergone multiple procedures on his right foot and and has had surgery on his left ankle.
"From day one, I said that's our priority," King told reporters after the draft. "They know it, and I think they wanna be back. You get a vibe from guys being around, you get a vibe and feel that they want to be a part of it. But we have tools that are in our favor to keep them."
The Nets, who traded center Mason Plumlee in a draft-night deal to acquire athletic Arizona Wildcats forward Rondae Hollis-Jefferson, own the Bird rights to both Lopez and Young, enabling the team to pay the two frontcourt players more than any other team can.
After playing in just 17 games in 2013-14 due to a season-ending foot injury, last season Lopez played in 72 games and averaged 17.2 points, 7.4 rebounds and 1.8 blocks.